TMEM45A Is Dispensable for Epidermal Morphogenesis, Keratinization and Barrier Formation

PLoS One. 2016 Jan 19;11(1):e0147069. doi: 10.1371/journal.pone.0147069. eCollection 2016.

Abstract

TMEM45A gene encodes an initially uncharacterized predicted transmembrane protein. We previously showed that this gene is highly expressed in keratinocytes where its expression correlates with keratinization, suggesting a role in normal epidermal physiology. To test this hypothesis, we generated TMEM45A knockout mice and found that these mice develop without any evident phenotype. The morphology of the epidermis assessed by histology and by labelling differentiation markers in immunofluorescence was not altered. Toluidine blue permeability assay showed that the epidermal barrier develops normally during embryonic development. We also showed that depletion of TMEM45A in human keratinocytes does not alter their potential to form in vitro 3D-reconstructed epidermis. Indeed, epidermis with normal morphogenesis were generated from TMEM45A-silenced keratinocytes. Their expression of differentiation markers quantified by RT-qPCR and evidenced by immunofluorescence labelling as well as their barrier function estimated by Lucifer yellow permeability were similar to the control epidermis. In summary, TMEM45A gene expression is dispensable for epidermal morphogenesis, keratinization and barrier formation. If this protein plays a role in the epidermis, its experimental depletion can possibly be compensated by other proteins in the two experimental models analyzed in this study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Differentiation
  • Cell Membrane Permeability*
  • Cell Proliferation
  • Cells, Cultured
  • Epidermal Cells*
  • Epidermis / metabolism
  • Female
  • Humans
  • Keratinocytes / cytology*
  • Keratinocytes / metabolism
  • Male
  • Membrane Proteins / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Morphogenesis / physiology*
  • Organogenesis / physiology
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Skin Physiological Phenomena

Substances

  • Membrane Proteins
  • RNA, Messenger
  • TMEM45A protein, human

Grants and funding

AH is a research fellow funded by FRIA (Fonds de la Recherche Industrielle et Agricole, FNRS, Belgium). ER is financed by Televie grant (FNRS- National Funds for Scientific Research, Belgium).